Business Analytics

Pre-requisite

Before we begin

Please install and load the following packages

library(dplyr)
library(tidyverse)
library(patchwork)
library(ggiraph)
library(gghighlight)

Access lecture slide from the course landing page

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Learning Objectives

Annotations in ggplot

Content for this topic has been sourced from ggplot2. Please check out the work for detailed information.

• In addition to plotting your graph, you want to provide additional details to explain your graph
• Text annotations are useful in this case
• The annotate() function can be used for any kind of geometric object
• Let us begin by text annotations
• In the annotate() function, the type of geom is specified first
• Then, the positining is required (x and y coordinates in this case)
• This is followed by the label

 ggplot(mtcars, aes(x = wt, y = mpg)) +
   geom_point()+
   annotate("text", x = 4, y = 25, label = "Annotation Text")

Annotations in ggplot

Content for this topic has been sourced from ggplot2. Please check out the work for detailed information.

• Further, annotations can be customized

 ggplot(mtcars, aes(x = wt, y = mpg)) +
   geom_point()+
   annotate("text", x = 4, y = 25, label = "Annotation Text", colour = "orange", size = 8)

 ggplot(mtcars, aes(x = wt, y = mpg)) +
   geom_point()+
   annotate("text", x = 1:5, y = 6, label = "Annotation Text", colour = "orange", size = 3)

Annotations in ggplot

Content for this topic has been sourced from ggplot2. Please check out the work for detailed information.

• Similar to text annotation, other geoms can be used for annotations
• However, instead of x and y, xmin and xmax is used for coordinates of the rectangle
• Do you remember what alpha is used for?

 ggplot(mtcars, aes(x = wt, y = mpg)) +
   geom_point()+
   annotate("rect", xmin = 4.8, xmax = 5.7, ymin = 10, ymax = 18.6, alpha = .2)

Annotations in ggplot

Content for this topic has been sourced from ggplot2. Please check out the work for detailed information.

• Suppose you want to add a line segment to your graph
• annotate() over here requires x and xend coordinates

 ggplot(mtcars, aes(x = wt, y = mpg)) +
   geom_point()+
   annotate("segment", x = 4.8, xend = 5.7, y = 10, yend = 18.6, colour = "red")

Scales